DNA and gram staining

Created by

Ebony stevens

Cards (21)

in gram staining, different chemicals are used to stain the bacteria different colours, depending on what type they are
what is crystal violet? 
a purple stain which will indicate gram-positive bacteria
how long does crystal violet need to sit for? 
60 seconds
what is grams iodine? 
it will fix the dye to the cell walls of the bacteria and make it permanent
how long does grams iodine need to sit for? 
60 seconds
what is the purpose of 95% alcohol? 
it washes off the excess dye, leaving only the dye fixed to the bacteria
how long does the alcohol solution need to sit for? 
no more than 30 seconds
what is the purpose of safranin? 
it will stain the remaining bacteria pink, these bacteria are gram-negative
how long does safranin need to sit for? 
60 seconds
what order do the solutions need to be added?
crystal violet, grams iodine, 95% alcohol, safranin
a suspension bacteria is placed on a clean glass slide, allowed to dry and fixed with heat. each of the solutions are added, with the slide being rinsed after every one. the slide is then viewed under a microscope
DNA is a large molecule made up of nucleotides that form a double helix shape
what are the components of DNA?
sugar, phosphate and the nucleotide base
Adenine always pairs with thymine
guanine always pairs with cytosine
what are the four nitrogenous bases? 
adenine, cytosine, guanine, thymine
the sugar phosphate backbone is formed through covalent bonds between adjacent nucleotides.
when DNA is heated, it becomes unstable. at very high temperatures the strands denature. this involves the breaking of the hydrogen bonds that bind complementary bases together
the sugar phosphate backbones' ability to bond with a complimentary base results in the nitrogenous bases being located in the interior of the molecule
the structure of DNA influences its interactions with enzymes
the unique sequence of base pairs in an organisms' DNA influences gene expression and the presence of different traits